engleski

Development of nanostructured transparent electrodes for solar cells based on aluminium doped zincite

Modern solid-state solar cells are multi-layered composites ; such configuration allows immense area for upgrades but not without struggle. As the main problem of all modern photovoltaic devices we find the mutual dependence of layers, i.e. the difficulty to predict the exact behaviour due to complex transport mechanisms at the boundaries between thin-film interfaced to other layers. Among such constituents, we find transparent electrodes or transparent conducting oxide layers (TCO), primarily aluminium doped zincite (AZO). AZO is a system thought to be well known, yet synthesis and deposition, chemical modifications, nano-morphological and nano-structural organisation parameters are still not unambiguously related to final functionality. For example, it is not clear how nanostructurisation of AZO would affect light trapping and vertical conductivity, while retaining of lateral conductivity for same thickness of films. The questions regarding general compatibility in interfacing of adjacent layers in SC also remain unclear. The benefits of AZO are thermal stability and mild deposition conditions. We follow these benefits and here we show evaluation of various softer chemical deposition methods for preparing AZO in planar configuration, as well as nanostructured, vertically aligned AZNR films that will retain conductivity, transparency and layer interconnectivity. The successfulness of the synthesis method was checked by means of GIXRD, FTIR-ATR and SEM/EDS. PL/DRS-UV-VIS and DLTS monitored compositional parameters behind transparency as well as lateral and perpendicular conductivity. In addition, parameters from profilometry, contact angle and TEM/EELS analysis shed more light on what synthesis seem to be more favourable for specific property. The utilisation of the observed parameters and behaviour was discussed from the point of view of TCO and CTO performing solar cell layers. The concept of developed material may shift the strategies of the solar cell design. This investigation of AZNR may cause the reconsideration of the paradigm of solar cell assembly since the AZNR additionally show conceptual similarities with charge transfer oxide (CTO) layers.

zincite nanorods ; solar cells ; DLTS ; SS IS

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